145. Solving a chemistry problem

73. In determining the lead content in a biological object, the “standard additive method” was used. For analysis, 50.00 ml of the test solution was taken and transferred to two separatory funnels. In one of them added 0.50 ml of a standard lead solution with a concentration of 0.060 g / l. Lead was determined by the extraction method with diethyl ammonium diethyldithiocarbamate in chloroform. The lead content in the organic phase was determined by the atomic absorption method with an emission line at 283.3 nm. Determine the concentration (mg / l) of lead in the analyzed object, if the absorption of the lead extract in the analyzed solution and in the solution with the addition of a standard lead solution is equal to 0.300 and 0.620, respectively.